Bluetooth: Controller: Apply suggestions from code review

Apply suggestions from code review.

Co-authored-by: Piotr Pryga <piotr.pryga@nordicsemi.no>
Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>

Author: 2 people

subsys/bluetooth/controller/ll_sw/nordic/lll/lll_conn.c

@@ -723,6 +723,11 @@ void lll_conn_pdu_tx_prep(struct lll_conn *lll, struct pdu_data **pdu_data_tx)
 			p->ll_id = PDU_DATA_LLID_DATA_CONTINUE;
 
 #if defined(CONFIG_BT_CTLR_DF_CONN_CTE_TX)
+			/* BT 5.3 Core Spec does not define handling of CP bit
+			 * for PDUs fragmented by Controller, hence the CP bit
+			 * is set to zero. The CTE should not be transmitted
+			 * with CONTINUE PDUs if fragmentation is performed.
+			 */
 			p->cp = 0U;
 			p->resv = 0U;
 #endif /* CONFIG_BT_CTLR_DF_CONN_CTE_TX */
@@ -1002,6 +1007,11 @@ static void empty_tx_init(void)
 
 	p = (void *)radio_pkt_empty_get();
 	p->ll_id = PDU_DATA_LLID_DATA_CONTINUE;
+
+	/* cp, rfu, and resv fields in the empty PDU buffer is statically
+	 * zero initialized at power up and these values in this buffer are
+	 * not modified at runtime.
+	 */
 }
 
 #if defined(CONFIG_BT_CTRL_DF_CONN_CTE_RX)

subsys/bluetooth/controller/ll_sw/ull_conn.c

@@ -2052,8 +2052,6 @@ uint16_t ull_conn_lll_max_tx_octets_get(struct lll_conn *lll)
 
 /**
  * @brief Initialize pdu_data members that are read only in lower link layer.
- *        Fields that are modified after static initialization are only
- *        re-initialized.
  *
  * @param pdu_tx Pointer to pdu_data object to be initialized
  */